Lion's Mane Jellyfish

Lion's Mane Jellyfish (Cyanea capillata) as seen in our Oregon Coast exhibit.

This animal is not part of an Aquarium exhibit. It a wild species that lives in the open sea and in Oregon coastal waters. It is included here as part of the Aquarium's mission to educate about the entire Oregon coastline.

The Lion’s Mane Jellyfish is not only the largest jellyfish in the world (one specimen measured 120 feet [36.5 meters] – which is longer than the Blue Whale), it is also one of the more dangerous varieties. Its body structure is similar to other jellyfish with a bell-shaped “body” that contains its digestive and reproductive organs above, and a thick mass of dangling tentacles below. These tentacles – which can number over one hundred on some specimens – are loaded with special stinging cells called nematocytes. These cells can deliver large doses of neurotoxins to other animals, which is the Lion’s Mane Jellyfish’s main form of defense. In humans, these stings can differ in severity from person to person. Healthy people may only encounter a painful rash, while others will have to enduring severe, painful blistering, muscle cramps, breathing problems and even death. Fans of Sir Arthur Conan Doyle’s Sherlock Holmes stories may recognize this jellyfish from one of those famous mysteries. In “The Adventure of the Lion’s Mane,” this particular animal caused the death of a school professor who inadvertently swam with some offshore.

Range & Habitat

Like all jellyfish, the Lion’s Mane must rely on the ocean’s currents to find food and travel from place to place. They can often be spotted near shore and in the upper 65 feet (20 m) of water from Alaska to southern California.

Conservation Status